Wet wiper arms, that is, wiper arms communicating windshield washer fluid to the windshield, are well-known in the art of windshield wipers. However, these wet wiper arms are of multiple piece construction and have been used with single sheet cowls.
Wiper arms in general are typically mounted in a cowl bridging a gap between a back wall of the engine compartment and a lower edge of the windshield. Fluid for wet wiper arms must be transported from a reservoir below the cowl to the blade above the cowl. This needs to be done without interfering with the windshield wiper arm as the blade is moved across the windshield. The arm is commonly used as a conduit for the fluid because the arm passes through the cowl and moves with the blade.
The windshield wiper arm has a bellcrank configuration, comprising a pivot, a crank and a blade mount. The pivot is commonly elongated in the form of a shaft or a sleeve. The crank projects from one end of the pivot. The blade mount projects from the opposite end of the pivot and is offset from the crank.
The pivot is rotatably mounted to the cowl. The crank is connected to a drive mechanism on a bottom side of the cowl. The blade mount is connected to an arm extension above the cowl, the arm extension being in turn connected to the blade.
With single sheet cowls, the pivot passes through, and is rotatably supported by, a cylindrical sleeve fixed to the cowl. This configuration requires the arm be of multiple piece construction. One of the crank and the blade mount must be separable from the pivot sleeve to facilitate the pivot passing through the cowl sleeve. An advantage of this configuration with regard to communicating fluid is that it easily accommodates the provision of a center cavity in the pivot which can be used to fluidly connect the reservoir under the cowl with fluid outlets above the cowl. Typically, fluid has been supplied directly to the pivot beneath the cowl, from where it travels to the blade mount above the cowl.
Integral arms are generally employed with dual flange or dual sheet cowls as is shown in U.S. Pat. No. 4,893,865, to McClain et al., issued Jan. 16, 1990, and assigned to the assignee of the present invention. The dual sheets of the cowl sandwich the pivot of the arm. A bolt passes through first one sheet, then the pivot, and then the second sheet, rotatably fixing the arm to the cowl.
Because the pivot does not have to pass through a sleeve, the dual sheet cowl is able to accommodate integral wiper arms integrating the crank, the blade mount, and the pivot into a single piece. The crank projects below the cowl and the blade mount projects above the cowl when the arm is in the vehicle. However, the center of the pivot is unavailable for communicating fluid as it is occupied by the bolt about which the arm pivots.